Blowout Preventer with Intersecting Cavities

ABSTRACT

A BOP includes a housing defining a bore, a first cavity intersecting the bore and comprising a first central axis, and a second cavity intersecting the bore and comprising a second central axis. The first central axis and the second central axis are non-parallel and the first cavity and the second cavity partially overlap along a vertical axis of the BOP.

BACKGROUND

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

A blowout preventer (BOP) is installed on a wellhead to seal and control an oil and gas well during various operations. For example, during drilling operations, a drill string may be suspended from a rig through the BOP into a wellbore. A drilling fluid is delivered through the drill string and returned up through an annulus between the drill string and a casing that lines the wellbore. In the event of a rapid invasion of formation fluid in the annulus, commonly known as a “kick,” the BOP may be actuated to seal the annulus and to control fluid pressure in the wellbore, thereby protecting well equipment positioned above the BOP.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein:

FIG. 1 is a block diagram of an embodiment of a mineral extraction system;

FIG. 2 is a perspective view of an embodiment of a blowout preventer (BOP) with intersecting cavities that may be used in the mineral extraction system of FIG. 1;

FIG. 3 is a side view of the BOP of FIG. 2;

FIG. 4 is a partially cutaway perspective view of the BOP of FIG. 2;

FIG. 5 is a top view of the BOP of FIG. 2;

FIG. 6 is a side cross-sectional view of the BOP of FIG. 2 taken within lines 6-6 of FIG. 5;

FIG. 7 is a side cross-sectional view of the BOP of FIG. 2 taken within lines 7-7 of FIG. 5;

FIG. 8 is a top view of a portion of the BOP of FIG. 2;

FIG. 9 is a side cross-sectional view of the portion of the BOP of FIG. 2 taken within lines 9-9 of FIG. 8, wherein each ram of the BOP is in an unsealed position;

FIG. 10 is a side cross-sectional view of the portion of the BOP of FIG. 2 taken within lines 10-10 of FIG. 8, wherein each ram of the BOP is in the unsealed position;

FIG. 11 is a side cross-sectional view of the portion of BOP of FIG. 2 taken within lines 9-9 of FIG. 8, wherein each ram of the BOP is in a sealed position;

FIG. 12 is a side cross-sectional view of the portion of the BOP of FIG. 2 taken within lines 10-10 of FIG. 8, wherein each ram of the BOP is in the sealed position;

FIG. 13 is a bottom perspective view of an embodiment of a ram that may be used in the BOP of FIG. 2;

FIG. 14 is a bottom perspective view of an embodiment of rams that may be used in the BOP of FIG. 2;

FIG. 15 is a first side view of the rams of FIG. 14;

FIG. 16 is a second side view of the rams of FIG. 14;

FIG. 17 is a first front perspective view of the rams of FIG. 14;

FIG. 18 is a second front perspective view of the rams of FIG. 14;

FIG. 19 is a first side cross-sectional view of a portion of an embodiment of a BOP with a side outlet that may used in the mineral extraction system of FIG. 1;

FIG. 20 is a second side cross-sectional view of the portion of the BOP of FIG. 19;

FIG. 21 is a side cross-sectional view of an embodiment of a blowout preventer (BOP) with intersecting, non-circular cavities that may be used in the mineral extraction system of FIG. 1;

FIG. 22 is a perspective view of a ram that may be used in the BOP of FIG. 21;

FIG. 23 is a front view of the ram of FIG. 22; and

FIG. 24 is a side view of the ram of FIG. 22.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present disclosure will be described below. These described embodiments are only exemplary of the present disclosure. Additionally, in an effort to provide a concise description of these exemplary embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

The present embodiments generally relate to a blowout preventer (BOP) for a mineral extraction system. The BOP may include multiple sealing assemblies stacked axially relative to one another. Each sealing assembly may include a cavity and a pair of opposed rams, which move through the cavity toward one another to a sealed position to adjust the BOP to a closed position to block fluid flow through a bore of the BOP and away from one another to an unsealed position to adjust the BOP to an open position to enable fluid flow through the bore of the BOP. As discussed in more detail below, in the disclosed embodiments, vertically adjacent sealing assemblies may overlap (e.g., partially overlap) along a vertical axis of the BOP and are offset (e.g., rotated) relative to one another about a circumferential axis of the BOP. Furthermore, the rams may include a shape that enables the vertically adjacent rams to move toward and away from one another through the vertically adjacent cavities at the same time and that enables the vertically adjacent rams in the vertically adjacent cavities to be in sealed positions at the same time. These features may reduce a height of the BOP or enable the BOP to include additional sealing assemblies without increasing the height of the BOP, for example.

While the disclosed embodiments are described in the context of a drilling system and drilling operations to facilitate discussion, it should be appreciated that the BOP may be adapted for use in other contexts and during other operations. For example, the BOP may be used in a pressure control equipment (PCE) stack that is coupled to and/or positioned vertically above a wellhead during various intervention operations (e.g., inspection or service operations), such as wireline operations in which a tool supported on a wireline is lowered through the PCE stack to enable inspection and/or maintenance of a well. In such cases, the BOP may be adjusted from the open position to the closed position (e.g., to seal about the wireline extending through the PCE stack) to isolate the environment, as well as other surface equipment, from pressurized fluid within the well. In the present disclosure, a conduit may be any of a variety of tubular or cylindrical structures, such as a drill string, wireline, Streamline™, slickline, coiled tubing, or other spoolable rod.

With the foregoing in mind, FIG. 1 is a block diagram of an embodiment of a mineral extraction system 10. The mineral extraction system 10 may be configured to extract various minerals and natural resources, including hydrocarbons (e.g., oil and/or natural gas), from the earth or to inject substances into the earth. The mineral extraction system 10 may be a land-based system (e.g., a surface system) or an offshore system (e.g., an offshore platform system). As shown, a BOP 16 (e.g., a multi-cavity BOP) is mounted to a wellhead 18, which is coupled to a mineral deposit via a wellbore 26. The wellhead 18 may include any of a variety of other components such as a spool, a hanger, and a “Christmas” tree. The wellhead 18 may return drilling fluid or mud toward the surface 12 during drilling operations, for example. Downhole operations are carried out by a conduit 24 (e.g., drill string) that extends through a bore 28 (e.g., central flow bore) of the BOP 16, through the wellhead 18, and into the wellbore 26.

To facilitate discussion, the BOP assembly 16 and its components may be described with reference to a vertical axis or direction 30 (e.g., axial axis or direction), a first horizontal axis or direction 32 (e.g., lateral axis or direction), a second horizontal axis or direction 34 (e.g., lateral axis or direction), and a circumferential axis or direction 36 (e.g., about the vertical axis 30). The BOP 16 may include multiple sealing assemblies stacked along the vertical axis 30 relative to one another. However, vertically adjacent sealing assemblies may overlap (e.g., partially overlap) along the vertical axis 30 and are offset (e.g., rotated) relative to one another about the circumferential axis 36. Each of the sealing assemblies includes a cavity and a pair of opposing rams, and each ram includes a shape that enables the vertically adjacent rams to move through the bore 28 at the same time and that enables the vertically adjacent rams in the vertically adjacent cavities to be in sealed positions at the same time.

FIGS. 2 and 3 illustrate a perspective view and a side view, respectively, of an embodiment of the BOP 16. As shown, the BOP 16 includes a housing 40 (e.g., body) that defines the bore 28 that receives the conduit 24. While the housing 40 is shown as a one-piece structure, it should be appreciated that the housing 40 may be formed from multiple separate parts that are coupled to one another. The housing 40 supports multiple sealing assemblies. In the illustrated embodiment, the housing 40 supports a first sealing assembly 42, a second sealing assembly 44, a third sealing assembly 46, and a fourth sealing assembly 48. However, the housing 40 may support any suitable number of sealing assemblies (e.g., 1, 2, 3, 4, 5, 6, 7, 8, or more). It should be appreciated that the terms “first,” “second,” “third,” and “fourth” are used herein merely to facilitate discussion and to differentiate similar components from one another.

Furthermore, each sealing assembly includes opposed cylinders (e.g., bonnets and/or actuator housings) that are coupled to and/or extend outwardly from the housing 40. In particular, the first sealing assembly 42 includes a first pair of opposed cylinders 52, the second sealing assembly 44 includes a second pair of opposed cylinders 54, the third sealing assembly 46 includes a third pair of opposed cylinders 56, and the fourth sealing assembly 48 includes a fourth pair of opposed cylinders 58. As discussed in more detail below, each sealing assembly also includes a cavity that intersects the bore 28 and that may be defined at least in part by the opposed cylinders, as well as a pair of opposed rams that move within the cavity.

The sealing assemblies are arranged such that vertically adjacent cavities overlap (e.g., partially overlap) along the vertical axis 30 and are offset (e.g., rotated) relative to one another about the circumferential axis 36. In the illustrated embodiment, the vertically adjacent cavities are offset by approximately 90 degrees (e.g., a first central axis 60 of a cavity of the first sealing assembly 42 is orthogonal to a second central axis 62 of a cavity of the second sealing assembly 44). However, the vertically adjacent cavities may be offset by greater or lesser angles (e.g., between approximately 30 to 90, 30 to 60, or 45 to 90 degrees).

FIG. 4 is a partially cutaway perspective view of a portion of the BOP 16. In particular, a portion of the housing 40 and all of the opposing cylinders shown in FIGS. 2 and 3 are removed for clarity. Each sealing assembly includes a cavity that intersects the bore 28 and a pair of opposing rams that move within the cavity. For example, in the illustrated embodiment, the first sealing assembly 42 includes a first cavity 70 and rams 72. Similarly, the second sealing assembly 44 includes a second cavity 80 and rams 82, the third sealing assembly 46 includes a third cavity 90 and rams 92, and the fourth sealing assembly 48 includes a fourth cavity 100 and rams 102.

To facilitate discussion, the rams of each sealing assembly are in a respective sealed position 106, and the rams are pipe rams that seal about the conduit 24 in the sealed position 106. To effectuate the seal, each pipe ram includes one or more packers 108 (e.g., elastomer packer), which are only labeled on one of the rams 72 of the first sealing assembly 42 for image clarity. It should be appreciated that various other types of rams (e.g., blind rams, shear rams) may be utilized in various combinations. Additionally, in operation, the rams may not all be in sealed positions 106 at the same time. Instead, one or more rams may be in the sealed position 106 at any given time. When at least one pair of opposed rams is in the sealed position 106, the BOP 16 may be in a closed position and may block fluid flow through the bore 28.

As shown, the vertically adjacent sealing assemblies overlap (e.g., partially overlap) along the vertical axis 30. In particular, the vertically adjacent cavities and the vertically adjacent rams of the vertically adjacent sealing assemblies overlap along the vertical axis 30. For example, the first sealing assembly 42 and the second sealing assembly 44 are vertically adjacent sealing assemblies (e.g., directly next to one another along the vertical axis 30), and the first sealing assembly 42 may be considered a lower sealing assembly and the second sealing assembly 44 may be considered an upper assembly based on their relative positions along the vertical axis 30 relative to the mineral deposit 25 (FIG. 1). Accordingly, an upper portion 120 (e.g., uppermost edge or surface) of the first cavity 70 of the first sealing assembly 42 may overlap a lower portion 122 (e.g., lowermost edge or surface) of the second cavity 80 of the second sealing assembly 44 along the vertical axis 30. That is, the upper portion 120 of the first cavity 70 of the first sealing assembly 42 may be positioned vertically above the lower portion 122 of the second cavity 80 of the second sealing assembly 44 along the vertical axis 30, while a lower portion 124 (e.g., lowermost edge or surface) of the first cavity 70 of the first sealing assembly 42 is positioned vertically below the lower portion 122 of the second cavity 80 of the second sealing assembly 44. In other words, the lower portion 122 of the second cavity 80 of the second sealing assembly 44 is positioned between the upper portion 120 and the lower portion 124 of the first cavity 70 of the first sealing assembly 42 along the vertical axis 30.

The rams may include a shape that enables the vertically adjacent rams to move toward and away from one another through the vertically adjacent cavities at the same time and that enables the vertically adjacent rams to be in their sealed positions 106 at the same time. For example, each ram 82 of the second sealing assembly 44 includes a wall 130 (e.g., curved, concave wall or surface) that defines a cutout region 132 on a lower side 134 of the ram 82. The cutout region 132 extends transversely across the ram 82 (e.g., transverse or cross-wise relative to a direction of movement of the ram 82; from a first lateral side of the ram 82 to a second lateral side of the ram 82), and the cutout region 132 receives or accommodates the rams 72 of the first sealing assembly 42 when the first and second sealing assemblies 42, 44 are in their respective sealed positions 106 (or otherwise positioned within the bore 28 at the same time). In this way, the vertically adjacent rams may nest (e.g., fit) into one another when in their respective sealed positions 106, and the vertically adjacent rams do not block one another from moving into and out of the bore 28 and/or from being positioned within the bore 28 (e.g., at the same time), even though the vertically adjacent rams overlap (e.g., partially overlap) along the vertical axis 30.

A gap 140 (e.g., vertical gap) may be provided between the vertically adjacent rams to enable each ram to move smoothly and efficiently between the unsealed position and the sealed position 106. Thus, the vertically adjacent rams may not contact one another as the vertically adjacent rams move between the unsealed position and the sealed position 106 at the same time (or while the vertically adjacent rams are otherwise positioned within the bore 28 at the same time, such as when the rams of the lower sealing assembly are moved toward the sealed position 106 while the upper sealing assembly is in the sealed position 106).

However, in some embodiments, the vertically adjacent rams may contact one another at least when the lower sealing assembly of the vertically adjacent sealing assemblies is in its sealed position 106. In such cases, a pressure within the wellbore 26 (FIG. 1) may exert a force on the rams of the lower sealing assembly and drive the rams of the lower sealing assembly vertically upward into contact with the rams of the upper sealing assembly that is positioned vertically above and adjacent to the lower sealing assembly. For example, if both the first sealing assembly 42 and the second sealing assembly 44 are in their sealed positions 106, the pressure within the wellbore 26 (FIG. 1) may exert a force on the rams 72 of the first sealing assembly 42 that is large enough to drive the rams 72 of the first sealing assembly 42 into contact with the rams 82 of the second sealing assembly 44. Accordingly, it may be desirable for the wall 130 that defines the cutout region 132 to have a shape (e.g., curvature) that generally corresponds to a wall 138 (e.g., curved, convex wall or surface) on an upper side 142 of the ram. For example, the wall 130 that defines the cutout region 132 on the lower side 134 of the rams 82 of the second sealing assembly 44 has a shape (e.g., curvature; radius of curvature) that generally corresponds to the wall 138 on the upper side 142 of the rams 72 of the first sealing assembly 42. Thus, the rams of the upper sealing assembly may physically support and/or provide a brace for the rams of the lower sealing assembly.

The relative position and the overlap between the vertically adjacent rams may provide other advantages. In some embodiments, the vertically adjacent rams may provide a different function (e.g., different than a function of the first pair of rams of the vertically adjacent rams and different than a function of the second pair of rams of the vertically adjacent rams) as the rams move toward or reach their sealed positions 106. In some embodiments, the vertically adjacent rams may improve a function of one or both pairs of the vertically adjacent rams. For example, the rams of one vertically adjacent sealing assembly may be pipe rams, and the rams of another vertically adjacent sealing assembly may be shear rams. In such cases, the rams of the one vertically sealing assembly may be capable of stabilizing the conduit 24 close (e.g., along the vertical axis 30; at a location that overlaps with the cavity of the other vertically adjacent sealing assembly) to the blades of the rams of the other vertically adjacent sealing assembly to improve the shearing function of the rams of the other vertically adjacent sealing assembly.

As discussed in more detail below, the vertically adjacent cavities and the vertically adjacent rams may only partially overlap along the vertical axis 30 (e.g., respective central axes of the vertically adjacent cavities are not aligned along the vertical axis 30; the first central axis 60 of the first cavity 70 of the first sealing assembly 42 is not aligned with the second central axis 62 of the second cavity 80 of the second sealing assembly 44 along the vertical axis 30). Such a configuration enables reduction in the vertical height of the BOP 16, while also enabling the vertically adjacent rams to be in respective sealed positions 106 at the same time (e.g., as opposed to configurations having multiple sealing assemblies offset about the circumferential axis 36 and aligned along the vertical axis 30).

Various degrees of overlap are envisioned. However, the vertically adjacent cavities and the vertically adjacent rams may overlap in a manner that enables all of the rams of the BOP 16 (or at least multiple rams of multiple different vertically adjacent sealing assemblies of the BOP 16) to have the same configuration (e.g., identical configuration or shape, such as the same arrangement of packers 108; the cutout region 132 having the same shape and dimensions). Such a configuration may facilitate manufacturing and/or maintenance of the BOP 16 (e.g., part replacement). In some embodiments, the vertically adjacent cavities and the vertically adjacent rams may overlap by between approximately 5 to 45 percent, 10 to 40 percent, 15 to 35 percent, or 20 to 30 percent. In some embodiments, the vertically adjacent cavities and the vertically adjacent rams may overlap by an amount equal to or less than approximately 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent (e.g., the first cavity 70 and the rams 72 of the first sealing assembly 42 may overlap or extend vertically across approximately 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent of a total vertical height of the second cavity 80 and the rams 82, respectively, of the second sealing assembly 44).

These features of the BOP 16 may be better understood with reference to FIGS. 5-12. For example, FIG. 5 is a top view of the BOP 16, FIG. 6 is a side cross-sectional view of the BOP 16 taken within lines 6-6 of FIG. 5, and FIG. 7 is a side cross-sectional view of the BOP 16 taken within lines 7-7 of FIG. 5. Various features (e.g., actuators that drive the movement of the rams; the one or more packers 108 [FIG. 4] of the rams) are removed for image clarity.

As shown, the rams are in their respective sealed positions 106 and the vertically adjacent rams nest (e.g., fit) into one another. In particular, a portion of the rams 72 of the first sealing assembly 42 are positioned within the respective cutout regions 132 of the rams 82 of the second sealing assembly 44, a portion of the rams 82 of the second sealing assembly 44 are positioned within the respective cutout regions 132 of the rams 92 of the third sealing assembly 46, and a portion of the rams 92 of the third sealing assembly 46 are positioned within the respective cutout regions 132 of the fourth sealing assembly 48. It should be appreciated that that the sealing assemblies may not be in their sealed positions 106 at the same time, but the configuration of the rams and cavities enables the rams of each sealing assembly to move independently between the unsealed and sealed positions 106 regardless of the position of other vertically adjacent rams in the BOP 16. For example, the rams 82 of the second sealing assembly 44 may move between the unsealed and sealed position 106 regardless of the position of the rams 72 of the first sealing assembly 42 and regardless of the position of the rams 92 of the third sealing assembly 46.

Similarly, FIG. 8 is a top view of a portion of the BOP 16. As shown, one cylinder and ram are removed from each sealing assembly. Various other features (e.g., actuators that drive the movement of the rams; the one or more packers 108 [FIG. 4] of the rams; the opposing ram and cylinder of each sealing assembly, and a side outlet) are also removed for image clarity. FIG. 9 is a side cross-sectional view of the portion of the BOP 16 taken within lines 9-9 of FIG. 8, and FIG. 10 is a side cross-sectional view of the BOP 16 taken within lines 10-10 of FIG. 8. In FIGS. 9 and 10, the rams are in respective unsealed positions 150 in which the rams are retracted or withdrawn from the bore 28 (e.g., to enable fluid flow through the bore 28). FIG. 11 is a side cross-sectional view of the portion of the BOP 16 taken within lines 9-9 of FIG. 8, and FIG. 12 is a side cross-sectional view of the BOP 16 taken within lines 10-10 of FIG. 8. However, in FIGS. 11 and 12, the rams are in respective sealed positions 106 in which the rams extend into the bore 28 (e.g., to seal about the conduit 24 or to otherwise block fluid flow through bore 28).

With one cylinder and ram removed from each sealing assembly, FIGS. 9-12 may facilitate understanding of the overlap (e.g., partial overlap) between the vertically adjacent cavities and the vertically adjacent rams. For example, with reference to FIG. 9, the first cavity 70 of the first sealing assembly 42 partially overlaps (e.g., along the vertical axis 30) the second cavity 80 of the second sealing assembly 44. As discussed above, the upper portion 120 of the first cavity 70 of the first sealing assembly 42 may overlap the lower portion 122 of the second cavity 80 of the second sealing assembly 44 along the vertical axis 30. That is, the upper portion 120 of the first cavity 70 of the first sealing assembly 42 may be positioned vertically above the lower portion 122 of the second cavity 80 of the second sealing assembly 44 along the vertical axis 30, while the lower portion 124 of the first cavity 70 of the first sealing assembly 42 is positioned vertically below the lower portion 122 of the second cavity 80 of the second sealing assembly 44. In other words, the lower portion 122 of the second cavity 80 of the second sealing assembly 44 is positioned between the upper portion 120 and the lower portion 124 of the first cavity 70 of the first sealing assembly 42 along the vertical axis 30. Because the vertically adjacent rams are positioned within the vertically adjacent cavities, the vertically adjacent rams overlap (e.g., partially overlap) in a similar manner.

As noted above, the vertically adjacent cavities and the vertically adjacent rams may overlap by between approximately 5 to 45 percent, 10 to 40 percent, 15 to 35 percent, or 20 to 30 percent. In some embodiments, the vertically adjacent cavities and the vertically adjacent rams may overlap by an amount equal to or less than approximately 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent. For example, with reference to FIG. 9, the first cavity 70 of the first sealing assembly 42 may overlap or extend vertically across approximately 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent of a total vertical height 160 of the second cavity 80 of the second sealing assembly 44.

FIGS. 13-19 illustrate various views of an embodiment of the rams that may be utilized in the BOP 16. In particular, FIG. 13 illustrates a bottom perspective view of an embodiment of a ram that may be utilized in the BOP 16, and FIG. 14 illustrates a bottom perspective view of an embodiment of two rams that may be utilized in the BOP 16. Additionally, FIG. 15 illustrates a first side view of the two rams of FIG. 14, FIG. 16 illustrates a second side view of the two rams of FIG. 14, FIG. 17 illustrates a first front perspective view of the two rams of FIG. 14, and FIG. 18 illustrates a second front perspective view of the two rams of FIG. 14. To facilitate discussion, the rams are labeled as one ram 72 of the first sealing assembly 42 and one ram 82 of the second sealing assembly 44. Also, the rams are shown as blind rams that seal against the opposing ram to seal the bore 28; however, the rams may be adapted to be any suitable type of rams, such as pipe rams or shear rams.

As shown in FIG. 13, the ram 82 includes a ram body 170 that includes a recess 172 to receive and support the one or more packers 108 (FIG. 4). The recess 172 may extend laterally across a front surface 174 of the ram body 170 to position the one or more packers 108 to contact and to seal against the one or more packers of the opposed ram of the sealing assembly. The recess 172 may also extend along a lateral surface 176 (e.g., along a mid-line) of the ram body 170 and along the wall 138 of the ram body 170 to enable the one or more packers 108 to seal the bore 28 (FIG. 4) of the BOP 16.

The wall 130 of the ram body 170 also defines the cutout region 132. In the illustrated embodiment, at least part of the wall 130 is a curved, concave wall, and the cutout region 132 is essentially a curved groove that extends laterally across the lower side 134 of the ram body 170. However, the cutout region 132 may have various other shapes that enable the cutout region 132 to receive and/or accommodate a portion of a vertically adjacent ram (e.g., below the ram body 170 along the vertical axis 30). For example, the wall 130 may not be curved, and instead the cutout region 132 may be essentially a rectangular or square groove that extends laterally across the lower side 134 of the ram body 170.

The cutout region 132 may be open to or extend from the front surface 174 toward a rear surface 178 of the ram body 170. However, the cutout region 132 may be separated from the recess 172 in the front surface 174 by a thickness 180 (e.g., portion) of the ram body 170 along the vertical axis 30 and/or may not be open to the rear surface 178 of the ram body 170 (e.g., may be separated from the rear surface 178 by a thickness 182 [e.g., portion] of the ram body 170). Thus, the front surface 174 of the ram body 170 may have a first cross-sectional area and a first cross-section in the shape of a circular segment, while the rear surface 178 of the ram body 170 may have a second cross-sectional area greater than the first cross-sectional area (e.g., due to the cutout region 132 not being open to the rear surface 178) and a second cross-section generally in the shape of a circle. The second cross-section may be generally in the shape of a circle (e.g., a circle with a notch in an edge due to a slot 183). The slot 183 may extend from the rear surface 178 to the cutout region 132 along the lower side 134 of the ram 82 to enable a fluid (e.g., mud) to travel from the bore 28 (FIG. 1) to the rear surface 178 of the ram 82. The slot 183 is not shown in FIGS. 2-12 and 14-24 for clarity, but it should be appreciated that any of the rams disclosed herein may include the slot 183.

These features of the rams can be further understood with reference to FIGS. 14-18, which illustrate the ram 72 overlapping (e.g., nested within) the ram 82 (e.g., as in the sealed position 106, such as in FIG. 4). Various parts of the ram 82 discussed above with respect to FIG. 13 are labeled in FIGS. 14-18, and it should be appreciated that the ram 72 may include the same parts and features. Similarly, any of the rams (e.g., the rams 92, the rams 102) in the BOP 16 may include the same parts and features. In particular, with reference to FIG. 15, the cutout region 132 of the ram 82 extends from the front surface 174 toward the rear surface 178. However, the cutout region 132 is separated from the recess 172 in the front surface 174 by the thickness 180 of the ram body 170 and/or is separated from the rear surface 178 by the thickness 182 of the ram body 170.

Additionally, the ram 82 has a total ram vertical height 184 and the cutout region 132 has a total cutout vertical height 186. The total cutout vertical height 186 may be between approximately 5 to 45 percent, 10 to 40 percent, 15 to 35 percent, or 20 to 30 percent of the total ram vertical height 184. In some embodiments, the total cutout vertical height 186 may be equal to or less than approximately 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent of the total ram vertical height 184. Because the ram 72 may generally nest within the cutout region 132 of the ram 82, the ram 72 may overlap or extend vertically across approximately 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent of the total ram vertical height 184 of the ram 82 when both rams 72, 82 are in the sealed positions 106. Notably, the degree of overlap of the rams 72, 82 may enable both rams 72, 82 to have the same configuration (e.g., identical configuration or shape, such as the same arrangement of packers 108; the cutout region 132 having the same shape and dimensions). FIGS. 15 and 16 also illustrate the gap 140 between the rams 72, 82.

In some embodiments, the BOP 16 may have one or more side outlets (e.g., choke/kill outlets). For example, the BOP 16 may include one or more side outlets that couple to a choke line that removes fluid (e.g., wellbore fluid) from the bore 28 of the BOP 16 when the BOP 16 is in the closed position and one or more outlets that couple to a kill line that provides fluids (e.g., mud) into the bore 28 when the BOP 16 is in the closed position. The one or more side outlets may be positioned at various locations about the BOP 16. In the disclosed embodiments, the one or more side outlets may advantageously be positioned to align (e.g., along the vertical axis 30) with the respective cutout regions 132 of the rams of one or more of the sealing assemblies of the BOP 16

For example, FIG. 19 is a first side cross-sectional view of a portion of an embodiment of the BOP 16 having a first side outlet 200 (e.g., one of a choke outlet or kill outlet) and a second side outlet 202 (e.g., one of a choke outlet or a kill outlet) aligned with the cutout regions 132 of the rams 72, and FIG. 20 is a second side cross-sectional view of the portion of the BOP 16 with the first side outlet 200. When the rams 72 are in the sealed position 106, fluid from the bore 28 may flow out through one of the first side outlet 200 or the second side outlet 202 to a choke line, and fluid may be pumped from a kill line into the bore 28 via the other one of the first side outlet 200 or the second side outlet 202.

The cutout regions 132 of the rams 72 and the position of the side outlets 200, 202 to align with the cutout regions 132 of the rams 72 may reduce the vertical height of the BOP 16. In some embodiments, a respective pair of the side outlets 200, 202 may be provided beneath each set of opposing rams and aligned with the respective cutout regions of each set of opposing rams within the BOP 16. In some such cases, the vertically adjacent rams and the vertically adjacent cavities may not overlap with one another along the vertical axis 30, but instead may overlap with the side outlets 200, 202 along the vertical axis 30. In some embodiments, the side outlets 200, 202 may at least be provided beneath and aligned with the respective cutout regions of the opposing rams of the lowermost sealing assembly.

While FIGS. 2-20 generally illustrate the BOP 16 with the cavities having a circular cross-sectional shape and/or rams for use in the cavities having the circular cross-sectional shape, the cavities may have a non-circular cross-sectional shape (e.g., oblong, oval, rectangle). With the foregoing in mind, FIG. 21 is a perspective view of an embodiment of the BOP 16 with intersecting, non-circular cavities. Various features (e.g., actuators that drive the movement of the rams; the cylinders that house the rams) are removed for image clarity.

As shown, the first sealing assembly 42 includes the first cavity 70 and rams 72. Similarly, the second sealing assembly 44 includes the second cavity 80 and rams 82, the third sealing assembly 46 includes the third cavity 90 and rams 92, and the fourth sealing assembly 48 includes the fourth cavity 100 and rams 102. The sealing assemblies are arranged such that vertically adjacent cavities overlap (e.g., partially overlap) along the vertical axis 30 and are offset (e.g., rotated) relative to one another about the circumferential axis 36.

To facilitate discussion, the rams of each sealing assembly are in a respective sealed position 106, and the rams are pipe rams that seal about the conduit 24 (FIG. 1) in the sealed position 106. To effectuate the seal, each pipe ram includes one or more packers 108 (e.g., elastomer packer), which are only labeled on one of the rams 72 of the first sealing assembly 42 for image clarity. It should be appreciated that various other types of rams (e.g., blind rams, shear rams) may be utilized in various combinations.

The vertically adjacent rams may nest (e.g., fit) into one another when in their respective sealed positions 106, and the vertically adjacent rams do not block one another from moving into and out of the bore 28 and/or from being positioned within the bore 28 (e.g., at the same time), even though the vertically adjacent rams overlap (e.g., partially overlap) along the vertical axis 30. It should be appreciated that the BOP 16 of FIG. 21 may have any of the features disclosed above with respect to FIGS. 2-20, but may be adapted to include the cavities having a non-circular cross-sectional shape. For example, openings in the side walls of the housing 40 that partially define the cavities and that enable movement of the rams into the bore 28 may be non-circular.

FIG. 22 is a perspective view of a ram that may be used in the BOP 16 of FIG. 21, FIG. 23 is a front view of the ram of FIG. 22, and FIG. 24 is a side view of the ram of FIG. 22. To facilitate discussion, the ram is labeled as one ram 82 of the second sealing assembly 44. However, any of the rams (e.g., the rams 72, the rams 92, the rams 102) in the BOP 16 may include the same parts and features. Also, the ram 82 is shown as a pipe ram that seals about the conduit 24 (FIG. 1) to seal the bore 28; however, the ram 82 may be adapted to be any suitable type of ram 82, such as a blind ram or a shear ram.

In FIGS. 22-24, the ram 82 includes the ram body 170 that has a non-circular cross-sectional shape (e.g., oblong, oval, rectangle). For example, as shown in FIG. 23, a width 210 of the ram 82 (e.g., along the lateral axis 34 of FIG. 21) is greater than a height 212 of the ram 82 (e.g., along the vertical axis 30 of FIG. 21). The ram 82 also includes the recess 172 to receive and support the one or more packers 108 (FIG. 21). The recess 172 may extend laterally across the front surface 174 of the ram body 170 to position the one or more packers 108 to contact and to seal against the conduit 24 (FIG. 1). The recess 172 may also extend along the lateral surface 176 (e.g., along a mid-line) of the ram body 170 and along the wall 138 of the ram body 170 to enable the one or more packers 108 to seal the bore 28 (FIG. 21) of the BOP 16.

The wall 130 of the ram body 170 also defines the cutout region 132. In the illustrated embodiment, at least part of the wall 130 is a curved, concave wall, and the cutout region 132 is essentially a curved groove that extends laterally across the lower side 134 of the ram body 170. However, the cutout region 132 may have various other shapes that enable the cutout region 132 to receive and/or accommodate a portion of a vertically adjacent ram (e.g., below the ram body 170 along the vertical axis 30). For example, the wall 130 may not be curved, and instead the cutout region 132 may be essentially a rectangular or square groove that extends laterally across the lower side 134 of the ram body 170.

The cutout region 132 may be open to or extend from the front surface 174 toward the rear surface 178 of the ram body 170. However, the cutout region 132 may be separated from the recess 172 in the front surface 174 by the thickness 180 (e.g., portion) of the ram body 170 along the vertical axis 30 and/or may not be open to the rear surface 178 of the ram body 170 (e.g., may be separated from the rear surface 178 by the thickness 182 [e.g., portion] of the ram body 170).

Additionally, with reference to FIG. 24, the ram 82 has the total ram vertical height 184 and the cutout region 132 has a total cutout vertical height 186. The total cutout vertical height 186 may be between approximately 5 to 45 percent, 10 to 40 percent, 15 to 35 percent, or 20 to 30 percent of the total ram vertical height 184. In some embodiments, the total cutout vertical height 186 may be equal to or less than approximately 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent of the total ram vertical height 184. Because the ram 72 (FIG. 21) may generally nest within the cutout region 132 of the ram 82, the ram 72 may overlap or extend vertically across approximately 45, 40, 35, 30, 25, 20, 15, 10, or 5 percent of the total ram vertical height 184 of the ram 82 when both rams 72, 82 are in the sealed positions 106. Notably, the degree of overlap of the rams 72, 82 may enable both rams 72, 82 to have the same configuration (e.g., identical configuration or shape, such as the same arrangement of packers 108; the cutout region 132 having the same shape and dimensions).

While the disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims. Furthermore, any of the features described with respect to FIGS. 1-24 may be combined in any suitable manner. 

1. A blowout preventer (BOP), comprising: a housing defining a bore; a first cavity intersecting the bore and comprising a first central axis; and a second cavity intersecting the bore and comprising a second central axis; wherein the first central axis and the second central axis are non-parallel and the first cavity and the second cavity partially overlap along a vertical axis of the BOP.
 2. The BOP of claim 1, wherein the first central axis and the second central axis are orthogonal to one another.
 3. The BOP of claim 1, wherein the first cavity extends vertically across between about 5 to 45 percent of the second cavity to cause the first cavity and the second cavity to partially overlap along the vertical axis of the BOP.
 4. The BOP of claim 1, comprising a first ram positioned in the first cavity and a second ram positioned in the second cavity, wherein the second ram comprises a cutout region on a lower side of the second ram, and the cutout region is configured to receive a portion of the first ram.
 5. The BOP of claim 4, wherein the cutout region comprises a curved groove that is defined by a curved wall of the second ram.
 6. The BOP of claim 4, wherein the cutout region enables the first ram and the second ram to be in respective sealed positions within the bore at the same time.
 7. The BOP of claim 1, comprising a side outlet formed in the housing and a ram positioned in the first cavity, wherein the ram comprises a cutout region on a lower side of the ram, and the side outlet is aligned with the cutout region along the vertical axis of the BOP.
 8. The BOP of claim 1, comprising a ram positioned in the first cavity, wherein the ram comprises: a front surface configured to face an opposing ram positioned in the first cavity; a rear surface that is opposite the front surface; and a cutout region on a lower side of the ram, wherein the cutout region extends from the front surface toward the rear surface, such that the front surface comprises a first cross-sectional shape of a circular segment, and the rear surface comprises a second cross-sectional shape of a circle with a notch.
 9. The BOP of claim 1, comprising a third cavity intersecting the bore and comprising a third central axis, wherein the first central axis and the third central axis are parallel to one another, and the second cavity and the third cavity partially overlap along the vertical axis of the BOP.
 10. The BOP of claim 9, comprising a first ram positioned in the first cavity, a second ram positioned in the second cavity, and a third ram positioned in the third cavity, wherein the second ram comprises a respective cutout region on a respective lower side of the second ram that is configured to receive a portion of the first ram, and the third ram comprises a respective cutout region on a respective lower side of the third ram that is configured to receive a portion of the second ram.
 11. The BOP of claim 10, wherein the second ram and the third ram have an identical shape.
 12. A blowout preventer (BOP), comprising: a housing defining a bore; a cavity intersecting the bore; and a ram positioned within the cavity and comprising a cutout region on a lower side of the ram that is configured to receive a portion of a vertically adjacent ram that is positioned adjacent to and below the ram along a vertical axis of the BOP.
 13. The BOP of claim 12, comprising the vertically adjacent ram and a vertically adjacent cavity through which the vertically adjacent ram moves, wherein the cutout region enables the ram and the vertically adjacent ram to be positioned within the bore at the same time.
 14. The BOP of claim 13, wherein the cavity and the vertically adjacent cavity are orthogonal to one another.
 15. The BOP of claim 12, wherein the cutout region comprises a curved groove that is defined by a curved wall of the second ram.
 16. A method of operating a blowout preventer (BOP), comprising: moving a first pair of opposing rams through a first cavity into a bore of the BOP; and moving a second pair of opposing rams through a second cavity into the bore of the BOP; wherein the first pair of opposing rams and the second pair of opposing rams partially overlap along a vertical axis of the BOP at least when both the first pair of opposing rams and the second pair of opposing rams are positioned within the bore of the BOP.
 17. The method of claim 16, comprising contacting and bracing the first pair of opposing rams using the second pair of opposing rams at least when both the first pair of opposing rams and the second pair of opposing rams are in respective sealed positions within the bore of the BOP.
 18. The method of claim 16, wherein moving the first pair of opposing rams through the first cavity into the bore of the BOP comprises moving the first pair of opposing rams toward one another along a first axis, and moving the second pair of opposing rams through the second cavity into the bore of the BOP comprises moving the second pair of opposing rams toward one another along a second axis that is orthogonal to the first axis.
 19. The method of claim 16, wherein moving the first pair of opposing rams through the first cavity into the bore of the BOP comprises moving the first pair of opposing rams into respective cutout regions defined on respective lower sides of each ram of the second pair of opposing rams at least when the second pair of opposing rams is positioned within the bore of the BOP.
 20. The method of claim 16, comprising moving a third pair of opposing rams through a third cavity into the bore of the BOP, wherein the second pair of opposing rams and the third pair of opposing rams partially overlap along the vertical axis of the BOP at least when both the second pair of opposing rams and the third pair of opposing rams are positioned within the bore of the BOP. 